CAREER: Rusting the Earth: the mechanisms and mineralogy of microbial Fe oxidation

微生物是数量众多、分布广泛、代谢多样的生物体，几乎影响着地球上的每一个环境。s表面。铁氧化微生物（FeOM）可能已经氧化，或？生锈，？地球数十亿年。在接近中性的pH环境中，FeOM形成铁羟基氧化物，吸附金属，有机物和其他营养物质，影响元素的生物利用度，C循环以及土壤和水质。微生物的铁氧化预计会加速铁氧化率在低氧，铁（II）丰富的环境中发现的环中性含水层和土壤，非生物氧化速率缓慢。然而，一些嗜酸性FeOM物种已明确显示氧化铁，因此，我们所知甚少的多样性，遗传学和生物化学的FeOM功能在中性pH值。我的总体目标是开发一个综合的微生物，生物化学，矿物学和地球化学的理解铁微生物氧化，以准确地描述现代和古代地球上的铁循环。因此，本项目的研究目标如下：（1）从地下水中分离和鉴定新的FeOM，从而扩展目前有限的FeOM多样性知识;（2）发现参与Fe氧化的关键基因/蛋白的候选者，深入了解生物（地质）化学机制，并使我们能够测定铁氧化和识别（Meta）基因组中的遗传能力;（3）研究微生物碳代谢及其相关基因，了解微生物铁氧化物对碳循环的影响。这项工作将涉及培养和生理表征，差异基因/蛋白质表达，qPCR，以及分离基因组和环境16 S rRNA和其他基因的测序和分析的组合。我们将与位于DE和PA的NSF克里斯蒂娜河流域临界区观测站（CRB-CZO）合作，使用CRB-CZO站点作为新型FeOM的来源，并作为我们检测FeOM存在和活动的新方法的试验场。研究主题将融入教育活动，培养学生创造性地思考和跨学科工作。创造力和跨学科的科学思想对于推进我们的社会和解决环境问题所需的创新和解决问题至关重要。这些技能需要实践，所以主要的教育目标是（1）开发一个基于探究的本科生地质微生物学类和（2）创建一个课程？野生微生物！为Serviam学院中人数不足的女中学生开设科学模块。我还将在项目过程中培训一名博士后研究员和一名博士生。这项研究将被纳入持续的推广计划，包括学校介绍，教师研讨会，学院？一年一度的海岸日，科学咖啡馆，和其他机会由DE海洋赠款办公室组织。

Microbes are numerous, widespread, and metabolically-versatile organisms, impacting virtually every environment on Earth?s surface. Fe-oxidizing microorganisms (FeOM) have likely been oxidizing, or ?rusting,? the Earth for billions of years. In near-neutral pH environments, FeOM form iron oxyhydroxides, which adsorb metals, organics, and other nutrients, affecting element bioavailability, C cycling, and soil and water quality. Microbial Fe oxidation is predicted to accelerate Fe oxidation rates in low oxygen, Fe(II)-rich environments found in circumneutral aquifers and soils, where abiotic oxidation rates are slow. However, few neutrophilic FeOM species have been unambiguously shown to oxidize Fe; therefore we know little about the diversity, genetics, and biochemistry of FeOM that function at neutral pH. My overall aim is to develop an integrated microbiological, biochemical, mineralogical and geochemical understanding of Fe microbial oxidation, in order to accurately describe modern and ancient Fe cycling on Earth. We first need to develop methods to recognize and quantify circumneutral microbial Fe oxidation and effects, so this project has the following research objectives: (1) Isolate and characterize novel FeOM from groundwater and thus expand the currently limited knowledge of FeOM diversity; (2) Discover candidates for key genes/proteins involved in Fe oxidation, to gain insight into bio(geo)chemical mechanisms and to give us the abilities to assay Fe-oxidation and recognize the genetic capability in (meta)genomes; (3) Characterize C metabolism and related genes in isolates, to understand how microbial Fe oxidizers can influence C cycling. This work will involve a combination of culturing and physiological characterization, differential gene/protein expression, qPCR, as well as sequencing and analysis of isolate genomes and environmental 16S rRNA and other genes. We will work in conjunction with the NSF Christina River Basin Critical Zone Observatory (CRB-CZO) in DE and PA, using CRB-CZO sites as a source of novel FeOM and as a testing ground for our new methods for detecting FeOM presence and activity. The research themes will be integrated into educational activities that train students to think creatively and work across disciplines. Creativity and interdisciplinary scientific thought is vital to the innovation and problem-solving needed to advance our society and address environmental issues. Such skills take practice, so the main educational objectives are to (1) develop an inquiry-based undergraduate geomicrobiology class and (2) create a curriculum for a ?Microbes in the Wild!? science module for under-represented female middle school students in the Serviam Academy. I will also train a postdoctoral researcher and a PhD student over the course of the project. The research will be incorporated into continuing outreach programs, including school presentations, teacher workshops, the college?s annual Coast Day, Science Café, and other opportunities organized by the DE Sea Grant office.